Which among the following drug is obtained from leaves?

Appeared in: WCL Staff Nurse - 2022

Explanation

Vincristine is a potent anti-cancer medication classified as a Vinca alkaloid.
It is extracted from the leaves of the Madagascar periwinkle plant, Catharanthus roseus.
This drug functions as a mitotic inhibitor, halting cell division, which is why it is effective against various cancers like leukemia and lymphoma.

Option A: Although Digitoxin is also derived from leaves (of the Foxglove plant, Digitalis purpurea), it is a cardiac glycoside, not an alkaloid. Given that two other options are alkaloids, Vincristine fits the pattern better as the intended answer.
Option B: Tubocurarine is an alkaloid, but it is extracted from the bark and stems of the plant Chondrodendron tomentosum, not the leaves.
Option C: Emetine is an alkaloid extracted from the roots and rhizomes of the Ipecac plant (Cephaelis ipecacuanha), not the leaves.

Clinical Relevance

Nursing practice connection: Knowing Pharmacognosy: Botanical Sources of Drugs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the natural source of drugs is a key component of pharmacognosy. Vinca alkaloids (Vincristine, Vinblastine) are a major class of chemotherapy agents, and their origin from the periwinkle plant is a classic example.
Nurses must be aware of the distinct toxicities of these plant-derived drugs. Vincristine's dose-limiting toxicity is peripheral neuropathy, whereas Digitoxin's is cardiotoxicity (arrhythmias).
This knowledge is crucial for patient monitoring and education. For example, a patient on Vincristine needs to be taught to report any numbness or tingling in their hands or feet immediately.

How to Approach the Question

First, identify the core of the question, which is to find the drug that originates from plant leaves.
Systematically review each option and recall its botanical source and the specific plant part used.
For Option A, Digitoxin comes from the leaves of the Foxglove plant.
For Option D, Vincristine comes from the leaves of the Periwinkle plant.
Recognize that there are two correct options based on the literal question. This is a sign of an ambiguous question and requires deeper analysis.
Look for a secondary pattern. Note that Tubocurarine, Emetine, and Vincristine are all classified as alkaloids, while Digitoxin is a glycoside. This chemical classification is the likely differentiator intended by the examiner.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 1 p. 15-17

E6 Medicine Davidson Principles Practice 24e p. 46-48

E6 Pharmacology Nursing Lilley 11e Part 1 p. 107-109

Practise the full WCL Staff Nurse - 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.